1997 ASTON MARTIN DB7 brakes

^?
Introduction
#
••t
*<;'..

Introduction '-^;^'^<-~'
^--"^^zfjj^^T^""

Workshop Manual Sections
The
DB7
Workshop Manual
is
divided .jnto,9seGtipnsE.a&foli
1 Engine

2.
Fuel,
Emission Control
and
Exhaust
3. Transmission

4.
Suspension
and
Steering
5. Brakes, Wheels
and
Tyres
6. Electrics
7. Chassis
and
Body
8.
Air
Conditioning
9. Aston Martin Diagnostic System
Procedure Numbering
The workshop manual procedures
are
numbered using
the
parts list numbers
as a key. The
first
two
digits
oi a

workshop manual procedure number
are
also
the
parts list number
(e.g.
1.5.01
Sump Removal relates
to PL 1.5 Oil

Pump
and
Sump). Thus when carrying
out a
procedure,
you can
quickly locate
the
relevant parts illustration
and

spare parts list.
To avoid excessive repetition, each procedure will
be
fully detailed once
in its
appropriate place
in the
manual.
In

any other location where this procedure
is
required,
it
will
be
referenced only
by its
title
and its
procedure number.
Special Tools
Where special service tools
are
required
to
perform
an
operation,
the
tool number
is
recorded
at the
point
of use

within
the
procedure.
An
index
and
illustrated list
is
provided
in
this section
for the
purpose
of
identifying special

tools.

References
References
to the
left, right, front
or
rear
of
the vehicle
or of
a component
are
always made as
if
sitting
in the
drivers
seat facing forward.
Any
such references
to
assemblies removed from
the
vehicle
are to the
normal orientation
of

the assembly when fitted
in the
vehicle.
Repairs
and
Replacements
Where replacement parts
are
required,
it is
essential that only genuine Aston Martin parts
are
used. Your attention
is drawn
to the
following points concerning repairs
and the
fitting
of
genuine Aston Martin parts
and
accessories:
• Safety features embodied
in the
vehicle
may be
impaired
if
other than genuine Aston Martin parts
are
fitted.
In certain territories, legislation prohibits
the
fitting
of
parts which
are not
produced
to the
manufacturers
specification.
• Adhere
to
torque wrench settings given
in
this manual.
• Locking devices, where specified, must
be
fitted.
If the
efficiency
of a
locking device
is
impaired during

removal,
it
must
be
renewed.
•
The
vehicle warranty
may be
invalidated
by the
fitting
of
other than genuine Aston Martin parts.
April
1997 Hi

^?
The Aston Martin Lagonda Diagnostic System
Contents
Installation Instructions
Introduaion 9-2
The Aston Martin Diagnostic System 9-2
Diagnostic System Cables 9-5
Base Station Installation 9-8
Problem Solving 9-16
Service Centres 9-21
Service and Maintenance 9-22
Technical Specifications 9-24
Operating Instructions
The Aston Martin Lagonda Diagnostic System 9-27
Software 9-29
Cable Setup 9-31
Diagnostic Sockets - 97 MY 9-31
Establishing Communications 9-32
System Menu Selections 9-32
PDU Use 9-32
Engine Diagnostics - 97 MY 9-33
Transmission Diagnostics 9-40
Climate Control Diagnostics 9-43
Anti-Lock Brakes Diagnostics 9-43
Passive Anti-Theft (PATS) Diagnostics 9-44
Airbag System Diagnostics 9-45
Seat Belt Pretensioner Diagnostics 9-47
Print Facility 9-49
Digital Multimeter 9-50
Diagnostic Trouble Codes 9-53
Datalogger 9-55
Datalogger Example 9-63
Training 9-66
OBD II Scan Tool 9-66
System Self Test 9-69
The Asterisk (*) Menu 9-69
System Setup 9-70
May 1996 9-1

The Aston Martin Lagonda Diagnostic System
Installation Instructions mm^^?
Diagnostic System Cables
311
^ri M
r 1
3130-0030-01 VIA-PDU Cable
^
ctfa

3130-0778-00-B Anti-Lock Brakes
3130-0064-01 Base Station-PDU Cable
3130-0475-00 Test Probes
VBA
3130-0024-01 Vehicle Battery Adapti
3130-0764-00 Road Test Ext Cable
9-6 May 1996

The Aston Martin Lagonda Diagnostic System
Users Guide "^7
Establishing Communications
when cable connections are completed, switch on the
vehicle ignition. The electronic control units will 'wake

up'
and communication between the selected control unit
and the PDU will be established.
As communication
is
established with the selected system,
a system menu similar to that below will be displayed.
System Menu Selections
The options for each vehicle system are described in detai
I

on the following pages but menu entries fall into the
following general areas:
Security
• Datalogger
• Diagnostic Trouble Code and
Alarm History Monitor
• RF Transponder Key Learning
• Exit a
o
Datalogger
The Datalogger function is described in detail using a
worked example at the end of this PDU Users Guide.
Diagnostic Trouble Codes
This application enables the PDU to monitor selected
control module trouble codes and provides the following
functions:
• Decode and display any trouble codes logged by
the control module being monitored.
• When supported by the module, decodeand display
enhanced trouble
codes,
together with any count of
the number of occurrences
• Clear all of the trouble codes and freeze frame data
logged in the control module.
• Monitor other data such as the alarm history in this
example.
Note: The 95model year Zytek engine management
system permits clearing of individual trouble codes
selected by the technician on the PDU.
System Specific Tests
These menu entries cover special tests required to program
ortest system specificfeatures. The following are examples
of tests provided:
Engine KOEO and KOER tests
OBDII Readiness test
Output State Control test
Throttle Potentiometer track test
Ignition Key Learn Menu
Remote Transmitter Key Learn Tests
Special Functions Programming
PATS
Security
Exit
Selecting and then confirming the exit option will return
the PDU to the Main Menu.
PDU Use
In the following
pages,
the use of the PDU on each vehicle
system is described.
Engine Diagnostics
Transmission Diagnostics
Climate Control Diagnostics
Anti-Lock Brakes Diagnostics
Passive Anti-Theft (PATS) Diagnostics
Security System Diagnostics
Airbag Diagnostics
Seat Belt Pretensioner Diagnostics
After these system specific descriptions, the following
general purpose functions are described:
Datalogger
Digital Multi-Meter
Diagnostic Trouble Codes
Printing
Training
OBD II Scan Tool
User Self-Test
9-32 September 1996

^^?
The Aston Martin Lagonda Diagnostic System
Users Guide
Transmission Diagnostics
Selecting 'Transmission from the vehicle area menu will
present the technician with the following transmission
diagnostic tools menu:
Transmission Diagnostic
• Datalogger
• Diagnostic Trouble Codes
o
The Datalogger function is fully described in the worked
example at the rear of this PDU Users Guide.
Transmission Datalogger
The PDU datalogger function may be used to monitor the
following transmission controller signals
DIGS Number of DTCs Logged
The Diagnostics status manager (DSM) receives and
processes fault information and decides when a DTC
should be logged and the MIL turned on (if enabled). The
actual total stored is indicated by the parameter DTCS.
FBRAKE Brake Switch
The footbrake switch signal is input to the
TCM.
The input
is normally at ground potential and goes open circuit
when the brakes are applied. If the torque converter
clutch is applied it will disengage when this signal is

detected.

FMA Actual Force Motor Current
The force motor regulates the transmission fluid pressure.
It is a variable force solenoid whose coil current is
determined by the TCM. Range 0 -1.245 amps. A driver
circuit limits excessive current flow and performs a
ratiometric comparison of Desired (commanded) Force
Motor Current and Actual Force Motor current. The
parameter monitors the Actual Force Motor current 1 Bit
= l/204.8amps.
HOT Hot Mode
The signal from the transmission temperature sensor is
used to control TCC and line pressure. It is also used in
many diagnostic signals and is a critical component for
OBD II. Above 120°C the TCC is on in 2nd, 3rd and 4th

gears.
This reduces transmission temperature by decreasing
the heat generated by the torque converter. It also
provides maximum cooling by routing transmission fluid
directly to the transmission cooler in the radiator. When
the Hot Mode is ON the bit is set to 1.
IGN+ Ignition Feed Positive
The TCM receives ignition voltage through TCM pin 53.
MD Desired Force Motor Current
The force motor regulates the transmission fluid pressure.
It is a variable force solenoid whose coil current is
determined by the TCM. Range 0 -1.245 amps. A driver
circuit limits excessive current flow and performs a
ratiometric comparison of Desired (commanded) Force
Motor Current. The parameter mon itors the Desired Force
Motor current 1 Bit = 1/204.8amps.
RATIO Actual Gear Ratio
The diagnostic detects malfunction in the transmission
output components by monitoring the actual gear ratio.
The actual gear ratio is calculated using input (Ni) and
output speed (No): Ratio = Ni/No. This is compared with
the standard gear ratio for each gear. Malfunction can be
defined as: actual gear ratio is not equal to any of the
standard gear ratios.
RPM Engine Speed
The engine speed signal is input from the instrument pack.
The
signal
origi
nates
at the crankshaft
sensor.
The crankshaft
sensor signal is modified by the PCM and the instrument
pack before being input to the TCM.
SSA Shift Solenoid A
Shift solenoid A is attached to the valve body and its outlet
is open to exhaust when it is switched off. A OFF - outlet
open - 2nd and 3rd gears selected. The solenoid is
energised by the TCM providing an internal ground to
close the outlet. A ON - outlet closed -1 st and 4th gears

selected.

SSB Shift Solenoid B
Shift solenoid B is attached to the valve body and its outlet
is open to exhaust when it is switched off. B OFF - outlet
open - 1st and 2nd gears selected. The solenoid is
energised by the TCM providing an internal ground to
close the outlet. B ON - outlet closed - 3rd and 4th gears

selected.

September 1996 9-41

^?
The Aston Martin Lagonda Diagnostic System
Users Guide
Climate Control Diagnostics
The air conditioning control module is located at the right
end of the air conditioning unit. Since this controller uses
a unique communications protocol, the PDU must be
connected directly to the unit via the Vehicle Inerface
Adaptor as shown in the following cable setup screen.
Cable Setup
Adigitalmicroprocessorwithin the control module receives
data signals from the operator controlled switches.
Comparison of these signals with those returned from
system temperature sensors and feedback devices results
in the appropriate output voltage changes needed to vary:
Blower motor speed, flap position and the solenoids
which respond to operator selected temperature demand.
The air from two blower motors is passed through the
evaporator matrix which, depending on the positions of
the humidity buttons, removes heat from the incoming air.
Dependingon the position of the two blend flaps, the cold
air either passes directly to the vehicle outlet vents, or is
passed through the heater matrix to be reheated and then
to the vehicle outlet vents.
The amount of air passing through the heater matrix is
infinitely variable depending on ambienttemperature and
the temperature selected within the vehicle.
Selecting 'Climate Control' from the vehicle area menu,
will presentthetechnician with the dataloggertool selection

screen.

Details of the signals which may be monitored in the
system may be found in the DB7 Workshop Manual -
Section 8 - Air Conditioning'
Anti-Lock Braking Diagnostics
The Teves Mk IV Braking System consists of two sub­
systems, power braking and anti-lock braking.
The PDU software(DataLogger) only allows the monitoring
of the anti-lock braking system.
The ABS System consists of:
Four wheel speed sensors.
One control module.
Seven solenoid valves.
One pressure switch.
One fluid level switch.
The ABS System
is
controlled and continuously monitored
by the ABS control module, which automatically
switchesoffthesystemifafailure is identified, illuminating
a warning lamp and leaving
full,
boosted braking to all
wheels. A wheel speed sensor is installed at each wheel.
Their wheel speed related signals are processed by the
control module, which triggers the solenoid valves to
modulate hydraulic pressure, preventing the wheels from

locking.
The control module also monitors the fluid
level and will inhibit ABS operation should lowfluid level
be detected.
The Datalogger function will permit monitoring of the
complete system apart from the solenoid valves. The
control module transmits short duration test pulses of 25
to 100 microseconds to the solenoid valves. These
pulses are too fast for the PDU to monitor and as a result
would cause confusing waveforms.
Selecting 'Anti-Lock Braking' from the vehicle area menu,
will present the technician with the following menu of
diagnostic tools screen:
Anti-Lock Brakes Diagnostic
Datalogger
Diagnostic Trouble Codes
o
ABS Diagnostic Trouble Codes
The DTCs which are supported in the Teves Mk IV ABS
system are listed in the workshop manual - Section 5
Brakes Wheels and Tyres.
September 1996 9-43

The Aston Martin Lagonda Diagnostic System
Users Guide
Em^'^?

ABS Datalogger
The following signals in the Teves Mk IV ABS system may
be monitored using the datalogger function.
DTCs Number of DTCs Logged
The Diagnostic status manager (DSM) receives and
processes fault information and decides when a DTC
should be logged and the MIL turned on. The actual total
stored is indicated by the parameter.
FBRAKE Brake Switch
The signal from the brake switch is used by the CM to
ensure that traction control is inhibited when the brakes
are applied. The input circuitry within the CM is a
1
OK
pull-up to ignition voltage. When the switch is closed the
parameter is set to 1.
FLWS Front Left Wheel Speed Sensor
An indication sensor outputs a sinusoidal wave form 48
pulses per revolution. The output is processed by the CM
to control braking and traction. The sensor is continually
monitored for open and short failure and operating range.
If its output exceeds 330km/h it is deemed to be faulty and
the CM is disabled. The parameter tracks the sensor
weaveform through 255 steps.
FRWS Front Right Wheel Speed Sensor
An indication sensor outputs a sinusoidal wave form 48
pulses per revolution. The output is processed by the CM
to control braking and traction. The sensor is continually
monitored for open and short failure and operating range.
If its output exceeds 330km/h it
is
deemed to be faulty and
the CM is disabled. The parameter tracks the sensor
weaveform through 255 steps.
RLWS Rear Left Wheel Speed Sensor
An indication sensor outputs a sinusoidal wave form 48
pulses per revolution. The output is processed by the CM
to control braking and traction. The sensor is continually
monitored for open and short failure and operating range.
If its output exceeds 330km/h it
is
deemed to be faulty and
the CM is disabled. The parameter tracks the sensor
weaveform through 255 steps.
RRWS Rear Right Wheel Speed Sensor
An indication sensor outputs a sinusoidal wave form 48
pulses per revolution. The output is processed by the CM
to control braking and traction. The sensor is continually
monitored for open and short failure and operating range.
If its output exceeds 330km/h it is deemed to be faulty and
the CM is disabled. The parameter tracks the sensor
waveform through 255 steps.
Passive Anti Theft (PATS) Diagnostics
Security System Diagnostics
Becauseof the requirementto maintain vehicle security,
the PATS and Security System operating instructions
and diagnostics are covered in the Vehicle Security
supplement to section 6 of the workshop manual. This
supplement has restricted circulation and is only
available to Aston Martin Dealers.
9-44 September 1996

^^?
The Aston Martin Lagonda Diagnostic System
Users Guide
The following trigger options are available:
Triggers when the signal passes above
a
specified

value,
i.e. stop lamp.
Triggers when the signal passes below
a
specified

value,
i.e. Anti-Lock brakes warning lamp.
Triggers when the signa
I
passes outside
a
specified

band,
i.e. oxygen sensor feedback.
Triggers when the signal passes into a specified

band.

Once the type of trigger has been selected the trigger
vaiue(s) (i.e. the signal level at which the trigger point wil
I

occur) should be set.
These values are set by highlighting the existing value.

i
jr:
ECT ^ 1
Trigger KBIT" ^
^^^^1

S.I.

°c
Oj
Engine coolant temperature

m
^
Highlighted Trigger Value
Press the calculator-style
icon.

A new screen should now be displayed.
Trigger Value Entry
Enter the required trigger value using the calculator-style
screen buttons.
The S.I. button enables unit selection, where applicable,
refer to S.I. Units.
Confirm the trigger value by pressing the 'tick'
icon.

The trigger screen will now be re-displayed.
Press the 'tick' icon to go back to the Parameter
Customisation screen.
Press the 'tick' icon again to return to the datalogger main

menu.

September 1996 9-59